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#989952 - 06/19/17 10:01 PM What terms are correct for describing the resistance of an open circuit?
kioolt Offline
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Registered: 09/06/01
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Do to a recent thread on this forum, I thought it would be a good idea to see what most people believe is the correct term or terms for describing the electrical resistance an open electrical circuit. Please give a short explanation of your choice. You may choose more then one selection.
Open circuit resistance
Multiple choices allowed


Votes accepted starting: 06/19/17 10:00 PM
You must vote before you can view the results of this poll.
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#989953 - 06/19/17 10:08 PM Re: What terms are correct for describing the resistance of an open circuit? [Re: kioolt]
dirtrider Offline
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Originally Posted By: kioolt
Do to a recent thread on this forum, I thought it would be a good idea to see what most people believe is the correct term or terms for describing the electrical resistance an open electrical circuit. Please give a short explanation of your choice. You may choose more then one selection.


Evening Kioolt

The common understanding of an open circuit resistance is (R = infinity) but depending on how far the open is & the humidity of the air around the open there is probably a slight measurable amount with the right equipment.
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#989954 - 06/19/17 10:13 PM Re: What terms are correct for describing the resistance of an open circuit? [Re: dirtrider]
kioolt Offline
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Loc: Bel Air, MD USA
Dirtrider,

I should have probable said for all practical purposes. I don't think I've ever seen any equipment that could measure the resistance of air but it probable does exist somewhere. But you are correct.
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1991 K100LT 128,700 miles
1982 R100RT 106,900 miles
Total 416,800 BMW miles

The cheapest thing on a BMW is the nut that connects the handlebars to the seat.

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#989955 - 06/19/17 10:58 PM Re: What terms are correct for describing the resistance of an open circuit? [Re: kioolt]
Twinsig Offline
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#989985 - 06/20/17 03:33 AM Re: What terms are correct for describing the resistance of an open circuit? [Re: Twinsig]
kioolt Offline
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Registered: 09/06/01
Posts: 983
Loc: Bel Air, MD USA
For the person or persons that voted zero resistance and no resistance could you please tell me what you think a short circuit measures?
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2004 R1150RT 181,200 miles
1991 K100LT 128,700 miles
1982 R100RT 106,900 miles
Total 416,800 BMW miles

The cheapest thing on a BMW is the nut that connects the handlebars to the seat.

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#990025 - 06/20/17 03:44 PM Re: What terms are correct for describing the resistance of an open circuit? [Re: kioolt]
Shiny Side Up Offline
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Originally Posted By: kioolt
For the person or persons that voted zero resistance and no resistance could you please tell me what you think a short circuit measures?

Could it be this:
If there is no complete circuit - then no notable resistance can be measured. (i.e. attempting to measure ground continuity between the ngative battery post and a disconnected gnd wire?) This is really "no continuity". But I do see what you're getting at with "infinite resistance".
A short is current bypassing an intended load and continuing to gnd, thereby blowing a fuse or the intended load not functioning.
I'm NOT an electronic engineer - just a guy trying to live in everybody else's world...
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#990027 - 06/20/17 03:52 PM Re: What terms are correct for describing the resistance of an open circuit? [Re: kioolt]
rxcrider Offline
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Registered: 09/16/11
Posts: 100
Loc: Ohio
I went with infinite, but it is really sort of voltage dependent. You'd think a gap from the ground to a cloud would be open enough to prevent an arc, but...

Originally Posted By: Shiny Side Up

Could it be this:
If there is no complete circuit - then no notable resistance can be measured. (i.e. attempting to measure ground continuity between the ngative battery post and a disconnected gnd wire?)


Hopefully that ground wire is disconnected at both ends, otherwise your meter probably just completed the circuit. Yes, the meter doesn't put out enough voltage to jump an air gap so an open circuit will show as infinite resistance (no needle movement) on an analog meter or open circuit on a digital meter. I think the confusion in people's brains is that no reading doesn't equate to no resistance, it equates to no circuit the meter is capable of measuring.


Edited by rxcrider (06/20/17 04:01 PM)
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#990033 - 06/20/17 04:58 PM Re: What terms are correct for describing the resistance of an open circuit? [Re: rxcrider]
kioolt Offline
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Registered: 09/06/01
Posts: 983
Loc: Bel Air, MD USA
Actually an open circuit does not give you no reading. The OL on my digital meter is a reading. It means over limit. The non movement of the needle on an analog is also a reading. It also could be interpreted as over limit. Out of range of the capabilities of the meter. But it definitely does not mean no or zero resistance. The OL on my digital meter means over 2 megohms. It's reading resistance even before you try to test the swtich, coil, etc. That's not zero or no resistance.
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2004 R1150RT 181,200 miles
1991 K100LT 128,700 miles
1982 R100RT 106,900 miles
Total 416,800 BMW miles

The cheapest thing on a BMW is the nut that connects the handlebars to the seat.

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#990048 - 06/20/17 07:30 PM Re: What terms are correct for describing the resistance of an open circuit? [Re: kioolt]
rxcrider Offline
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Registered: 09/16/11
Posts: 100
Loc: Ohio
Originally Posted By: kioolt
Actually an open circuit does not give you no reading. The OL on my digital meter is a reading. It means over limit. The non movement of the needle on an analog is also a reading. It also could be interpreted as over limit. Out of range of the capabilities of the meter. But it definitely does not mean no or zero resistance. The OL on my digital meter means over 2 megohms. It's reading resistance even before you try to test the swtich, coil, etc. That's not zero or no resistance.


Correct - I should have said no change in reading does not equate to no resistance. And why do I keep reading OL as open line instead of over limit - I really should remember that I've learned this a few times already. For that matter, the pegged needle on the analog meter doesn't say infinite either, just some max that it is capable of measuring. In all my entire post was in the correct spirit with a whole bunch of errors. Brilliant.


Edited by rxcrider (06/20/17 07:33 PM)
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#990084 - 06/21/17 02:09 AM Re: What terms are correct for describing the resistance of an open circuit? [Re: rxcrider]
Trobinson Offline
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Registered: 09/20/13
Posts: 311
Loc: San Antonio, TX
Originally Posted By: rxcrider
I went with infinite, but it is really sort of voltage dependent. You'd think a gap from the ground to a cloud would be open enough to prevent an arc, but...

Yes voltage plays its part since we see arcs in the sky with lightning, but this is extremely high voltage and actually corresponding low current (relatively speaking) due to the very high resistance of the air as measured by our simple 9vdc meters. grin
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